Tool eor sure aging valve-seats



M. B. SKINNER.

TOOL FOR SURFACING VALVE SEATS.

APPLICATION FILED SEPT.20.I918.

1 ,3 3 O, 9 1 5 Patented Feb. 17, 1920.

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MORTIMER B. SKINNER, 0F WILMETTE, ILLINOIS.

TOOL FOR SURFACING VALVE-SEATS.

Specification of Letters Patent.

Application filed September 20, 1918. Serial No. 254,940.

To all whom it may concern:

Be it known that I, MORTIMER B. SKIN- NnR, a citizen of the UnitedStates, and a resident of Wilmette, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements in Tools forSurfacing Valve-Seats, of which the following is a specification.

My invention relates to tools for surfacing the seats of valves. Itsprincipal object is to provide simple, strong and easily operable meansfor surfacing the valve seat as part of the operation of restoring thefit between valve-head and seat in internal combustion engines, such asin automobiles, after the parts have become worn in service, and meansfor making such repairs by the ordinary mechanic found in garages, andwithout the use of power machinery.

A prime specific object is to provide a simple form of device of thecharacter described in which the cutter is maintained tightly upon theseat provided therefor whereby a true surface may be out upon the partbeing operated upon. Other objects and advantages will appearhereinafter.

In the accompanying drawings, which form a part of this specification, Ihave illustrated these improvements in what I now consider the preferredform, Figure 1 being a sectional view of an engine part with theimproved reseating tool in operative position therein; Fig. 2 being amedial vertical section of the cutter at right angles to the view ofFig. 1, Fig. 3 being a top and sectional view as on line 3-3 of Fig. 1,and Fig. 4: being a fragment of a pilot stern of a different diameterfrom that of Figs. 2 and 3.

The tool illustrated comprises a cutter head 10 which is provided with adiametrical slot or recess 11 adapted to accommodate the outter 12snugly yet with enough looseness to permit it to be inserted and removedreadily. The cutter head 10 is also provided with a threaded axial holeor recess at 18 adapted to accommodate the threaded endl i of the pilotstem 15 or 16, which pilot stem may be of various diameters, asillustrated, so as to fit rotatably in valve stem openings of varioussizes in different makes or sizes of engines.

The function of the pilot stem 15 or 16 is to maintain the head 10 in atruly central relation to the valve seat being operated upon so that thecutter 12 will be carried in circular lines. Pilot stems have beenheretofore suggested on cgtter heads for such purpose. The head 10 ismilled diametrically forming what may be termed a bottom wall 17 whichconstitutes seat or rest for the cutter 12. This wall or seat 17 is aplane surface at right angles to the axis of the pilot stem 15 and thecutter 12 is provided with a flat surface adapted to rest upon the seat17. A hole or recess 18 is provided midway of the ends of the cutter 12to receive the tapering end of the screw 19 threaded radially into thehead 10 at right angles to the direction of the slot 11. By tighteningthe screw upon the cutter 12 with the end of the screw in engagementwith the hole 18 the cutter is centrally adjusted and maintained againstits longitudinal movement.

What may be termed the upper portion of the head 10 is provided with anaxial recess 22, which is screw threaded to receive the threaded portion23 of the driving shank 24:. Where the cutter 12 is provided withcutting edges, as 25, which are so formed as to take hold when the head10 is rotated in the usual clock-wise direction (viewing the device fromthe top as illustrated) the threads 23 of the shank 24C and those of therecess 22 will be right hand threads; or in other words, the shank 24:will thread into the head 10 when the shank is rotated in the operativedirection of rotation of the head and cutter. In the device illustratedthe end portion 26 of the shank 2a bears directly upon what may betermed the top surface of the cutter 12. It will thus be valve seat hasbecome irregular from un-.

equal wear, the tendency of the end portions of the cutter doing theresurfacing has been to follow the irregularities of the old valvesurface and substantially to reproduce them in the new surface, dueprincipally to the fact that the cutter has not beenheld with sutficientrigidity to prevent this yielding or rocking, as upon a middle screwsuch as 19.

Patented Feb. 17, 1920.

For rotating the cutter of the upper end of the stem 24 is squared andtapered at 30 for engagement by the jaws of a brace or breast drill. Ialso provide a lever bar 31 slidable in the cross-hole 32 in the shank,and at the upper end of the shank I provide the pintle 33 upon whichloosely rests the hand-piece 34. In making a good job or resurfacing itis important that theshank 24; be maintained in a constant direction. Ifind that this cannot be done where the pressure is applied by one ortwo hands to such a cross bar as 31, glmlet or anger fashion;

but that such -constant direction may be maintained if the downwardpressure be applied axially by one hand and upon a suiiiciently largeand pivoted cap or hand-piece, as 34:, while the rotative movement isapplied with the other hand, as upon the bar '31. I have claimed thisfeature in my copending application Serial Number 189,539, filed Sept.4, 1917, on tools for surfacing valve seats.-

An advantage of the present construction is that the several parts maybe readily separated from each other and carried in a small case or box.

I claim:-

ll In a tool of the character described, the combination of a cutterhead having a seat therein for a cutter, a cutter resting upon saidseat, said cutter having cutting edges arranged to cut when the head isrotated in a given direction, a driving shank threaded axially into saidhead and having the end portion of the shank bearing against said cutteron the side thereof opposite said seat to hold the same tightly uponsaid seat, the

enacting threads of said cutter and of said shank being in suchdirection that when rotating said head and cutter by said shank thetendency oi? the shank is to thread more tightly against said cutter.

The combination with the elements of claim 1 of means for centering thecutter in the cutter head.

3. The combination with the elements of claim 1 of pilot means forcentering the cutter head with respect to the valve seat to be operatedupon.

at. In a tool of the character described, the combination of a cutterhead having a seat for a cutter, a cutter resting against said seat, andclamping means for holding the cutter tightly upon said seat, saidclamping m ans includin a driving shank threaded axially into the cutterhead in a direction toward said seat with threads which lead the shankinto the head when the shank is rotated in the operative direction ofrotation of the head and cutter.

5. The combination with the elements of claim l of a screw devicecarried by the cutter head t'or centering the cutter therein.

6. The combination with the elements of claim l of a pilot stemprojecting axially from the cutter head for centering the cutter headwith respect to the valve seat to be operated upon.

7. The combination with the elements of claim 4 or a pilot stemprojecting axially from the cutter head for centering the cutter headwith respect to the valve seat to be operated upon.

MORTIMER B. SKINNER.

